Electrocardiographic prediction of lateral involvement in acute non-anterior wall myocardial infarction

- ST-segment elevation in V6 in the acute phase of non-anterior myocardial infarction predicts lateral involvement as expressed by the R/S ratio in V1 and Q-waves in V6 in the post reperfusion phase.
- In lead I ST-segment deviation predicts lateral involvement being correlated to height and surface of R in V1 and Q-waves in V6.
- A small group of Cx occluded patients (n = 10) showed a high correlation between ST-segment elevation in V6 with R/S ratio in V1. These findings suggest further research in this group.
- Lead V2 is no indicator of lateral involvement as expressed by QRS changes in V1 and V6 in the post reperfusion phase of non-anterior myocardial infarction.

PurposeRecent research has established that a tall R-wave in V1 indicates lateral wall involvement in non-anterior wall myocardial infarction (MI). The objective of this study was to assess the value of the admission electrocardiogram (ECG) to predict R-waves and consequently lateral wall damage in the late phase of non-anterior MI.MethodsECGs of 69 patients were analyzed. ST-segment changes in representative leads for lateral wall infarction such as V1, V2, V6 and I were correlated with the extent of QRS-wave changes in V1 and V6.ResultsST-segment elevation in V6 showed correlations with R/S ratio in V1 (r = 0.802, B = 0.440, P = < 0.001) and with the depth of Q-waves in V6 (r = 0.671, B = 0.441, P = 0.007). This correlation was higher in a small subgroup where the left circumflex branch (Cx) was the culprit vessel (r = 0.888, B = 1.469 and P = 0.018). ST-segment depression in lead I correlated with the height of R and the surface of R in V1 (height times width of R) (r = 0.542, B = − 0.150, P = 0.005 and r = 0.538, B = − 0.153, P = 0.005 respectively), especially in the subgroup without proximal occlusions of RCA (r = 0.711 and r = 0.699). ST-segment depression in lead I also predicted Q-waves in V6 (r = 0.538, B = 0.114, P = 0.006). ST-segment changes in V2 showed no significant correlation with either R- or Q-wave measurements.ConclusionsST-segment elevation in V6 in the acute phase of non-anterior MI predicts lateral involvement as expressed by the R/S ratio in V1 in the post reperfusion phase. A subgroup with Cx occlusion showed especially strong correlations, although the size of the group was small. In lead I ST-segment depression is correlated to height and surface of R in V1 and Q-waves in V6.